Hip and knee arthroplasty data for more than 200,000 procedures

What's the most common reason for hip or knee joint replacement? What are the most common reasons for joint revision surgery? What types of components are commonly used? The answers to these and many other questions about primary and revision hip and knee replacement procedures can be found in the latest annual report from the American Joint Replacement Registry (AJRR).

The 2014 Annual Report on Hip and Knee Arthroplasty Data will be released at the 2015 American Association of Hip and Knee Surgeons (AAHKS) Annual Meeting.

"The number of procedures in the registry grew by 164 percent since our first formal report last year," said Daniel J. Berry, MD, chair of the AJRR board of directors. "Our first report covered 80,227 procedures. This report covers the collection and analysis of 211,721 procedures related to hip and knee replacements that have taken place from 2012 through December 2014."

Procedural results
At the close of 2014, AJRR had hospital participants in all 50 states; the report includes data from 236 hospitals representing 45 states. The participating hospitals are diverse, and range from large teaching hospitals (56.7 percent) to small (1 to 99 beds) hospitals (21.1 percent).

The 2014 report provides in-depth analysis on 82,841 hip arthroplasties and 128,880 knee arthroplasties performed by more than 2,200 surgeons during the 3-year period (2012–2014). More than 18,000 revision procedures (8,257 hips and 10,420 knees) reported during the same period are also included.

According to AJRR data, more females than males received total joint replacements (59.7 percent versus 40.3 percent). The average patient age was 66.5 years, with nearly half of all procedures performed on individuals younger than age 65.

Osteoarthritis was the most common reason for both hip (78.4 percent) and knee (94.7 percent) arthroplasty. Data also indicated that rheumatoid arthritis is no longer a common indication for total joint replacement.

Just 747 hip resurfacing procedures were reported between 2012 and 2014, largely limited to a handful of hospitals and surgeons. Hemiarthroplasty was performed almost exclusively for the diagnosis of femoral neck fracture (93.6 percent of cases).

Loosening was the main cause overall for revision of primary total knee arthroplasty (TKA), noted in 19 percent of cases. However, infection was the primary reason for nearly half (43 percent) of all early TKA revisions (within 3 months of the primary procedures). Loosening and dislocation were the leading causes for all total hip arthroplasty (THA) revisions, accounting for 30 percent; dislocation and infection were the leading causes for early THA revisions, accounting for 34 percent.

Component metrics
The most common femoral head size was 36 mm in diameter, used in 45.4 percent of THAs. Overall usage of dual mobility articulations was approximately 1.6 percent of all THAs during the past 3 years. Dual mobility cups were used in approximately 7.0 percent of all revision hip arthroplasties but in only 1.3 percent of all primary THA procedures.

AJRR data show a steady and relatively rapid increase in the usage of ceramic heads during the past 3 years, with ceramic heads currently being used in nearly half of all THAs. Additionally, ceramic head usage has been biased toward younger patients.

Approximately one third of revision TKA patients received cross-linked polyethylene implants. The use of antioxidant polyethylene has increased from almost zero in 2012 to approximately 5 percent in 2014. More than 80 percent of TKAs involved patellar replacement.

Level II data collection
In 2014, AJRR conducted a pilot program to identify automated methods to acquire Level II data. Pilot hospitals were asked to submit Level II elements where possible. Twenty hospitals participated in the pilot program, submitting data on 8,126 procedures.

All hospitals were able to extract and report data on patient comorbidities (ICD-9) and American Society of Anesthesiologists (ASA) classification. However, lab values, prophylaxis, and the use of beta blockers were submitted only if the element was a discrete field in the hospital electronic medical record or if the data were captured in hospital (ie, lab tests were conducted in the hospital or at an outside location electronically linked with the hospital).

AJRR plans to increase the number of diagnosis codes to ensure adequate capture of comorbidities and complications. This issue will also be addressed by the increased granularity in coding required by the shift to ICD-10 coding. Finally, the pilot program showed that timing for capture of postoperative complications was a challenge. Consistent reporting and clearly defined data element definitions will aid in data capture in the future.

Looking ahead
As a multistakeholder, not-for-profit organization that seeks to optimize patient outcomes through collection of data on primary and revision hip and knee replacement procedures throughout the entire United States, the AJRR appreciates the ongoing support from the diverse stakeholders in the orthopaedic community. The continued growth and increased participation from hospitals and surgeons should enable AJRR to reach its goal of capturing more than 90 percent of all hip and knee replacement procedures performed nationally.

"We are thankful to the hospitals and surgeons who recognize the importance of a registry by entering their surgical data into the AJRR," said Dr. Berry. "We will continue our diligence in building a valuable national hip and knee arthroplasty registry that has a positive impact on patient care and the quality and durability of joint replacement surgery in the United States."

To access a copy of the AJRR 2014 Annual Report, visit www.ajrr.net.